You must work with other Lords to fight against powerful foes by joining an Alliance. You can find and join an Alliance or create your own from the Alliance menu on the bottom of the screen. You can join Public Alliances freely until they reach max capacity. An Alliance Member of Rank 4 or higher must approve your request in an invite only Alliance. You can spend 200 Gold to create your own if you can't find an Alliance you want. (Requires Citadel Lv 6).
[Joining, Leaving, and Disbanding Alliances]
1.) You can only join 1 Alliance at a time. If you want to join a different Alliance, you must first leave the Alliance you joined.
2.) You can leave your Alliance from the Manage Alliance menu within the Alliance menu.
3.) Alliance Leaders cannot leave the Alliance if there are any Alliance Members remaining. You can leave the Alliance after appointing a different Alliance Member as the Leader.
4.) If the Alliance Leader leaves the Alliance with no other Alliance Members in it, the Alliance will be disbanded and disappear forever.
Tip: Make sure to consider the consequences before leaving your Alliance.